[Incidence and clinical outcome of contrast-induced nephropathy in the elderly patients].

BACKGROUND: Aging is an established risk factor for contrast-induced nephropathy (CIN). However, little information is available on the incidence and clinical outcome of CIN for the elderly patients in Japan. OBJECTIVES: We determined the incidence and clinical outcome of CIN in the Japanese elderly patient. METHODS: We studied 292 patients who had mild renal dysfunction (estimated glomerular filtration rate (eGFR) 0.5 mg/dl above the baseline value at or within 2 days post procedure. RESULTS: Patients in the elderly group had a higher incidence of CIN (14%) than those in the control group (9%). In patients who developed CIN, there was no significant difference between the two groups in baseline GFR and GFR on days 1, 2, 7 and 30 after the procedure. However, the relative increase in GFR above baseline on day 7 (-4.0 ± 6.1 vs -8.3 ± 8.0 ml/min P=0.096) and day 30 (1.5 ± 9.4 vs -10.1 ± 9.6 ml/min P=0.0017) in the elderly group was higher than that in the control group. Furthermore, death occurred in 3 patients in the elderly group (20%) whereas no patient died in the control group (P=0.092). CONCLUSION: Aging (age ≥ 75) is a risk factor for CIN in Japanese. CIN in the elderly patients may be associated with prolonged renal dysfunction and poor prognosis.